1. Field of the Invention
This invention relates to a drive assembly which may initially be manually powered and which is adaptable to a bicycle type vehicle or other mechanisms whether or not manually powered and further wherein the drive assembly comprises a gear assembly comprising a plurality of gear pairs drivingly interconnected and specifically sized to maximize the out-put of the drive assembly.
2. Description of the Prior Art
Typically, cycle type vehicles such as a bicycle, which are manually powered, involve pedals turning a drive shaft in a typical and well accepted fashion. At least one drive gear or sprocket is fixedly secured to the drive shaft to rotate therewith when the operator applies manual force in the form of pedaling. This main drive gear or sprocket is connected by a sprocket chain or like device to a driven gear or sprocket secured to a drive axle normally attached to the rear wheel of the bicycle. Rotation of the drive shaft and the drive sprocket secured thereto causes rotation of the driven axle of the rear wheel and rotation thereof. During power is thereby supplied to the vehicle.
A more sophisticated drive assembly associated with bicycle-type vehicles as well as other manually powered devices include a drive assembly having a "gear changing" ability. In such a construction, a sprocket chain is transferable between each of a plurality of drive gears or sprockets attached to the drive shaft in spaced but generally immediately adjacent relation to one another. These drive sprockets are of a different size and accordingly rotation through the application of manual pedaling power of the drive shaft will cause each of the drive sprockets thereon to rotate at the same speed. However, due to the variance in the size of such a plurality of drive sprockets the rear driven axle to which the rear wheel is attached may rotate at varying speeds depending upon the transfer or placement of the interconnecting sprocket chain on a particular one of the plurality of drive sprockets. Assuming that the driven sprocket on the driven axle attached to the rear or power wheel of the bicycle is a first given size, the driven axle will be rotated at a greater speed when the interconnecting sprocket chain is driven by a larger diameter drive sprocket or gear than when the sprocket chain is attached to a smaller diameter drive sprocket or gear. Changing or the gears manually by the operator has its obvious advantages and such a drive assembly has enjoyed great popularity in recent years as evidenced by the consumer demand for performance bicycles commonly referred to as "ten speeds" or "three speeds".
While the above set forth prior art drive assemblies, particularly associated with bicycles, are operative and well accepted for their intended function. They are primarily designed to increase the operative performance in terms of speed characteristics and ease of pedaling of the cycle.
There is still a demand in the cycling art for a drive assembly which takes advantage of certain "lost energy" delivered to the drive axle of the vehicle such as when the operator is "coasting" after reaching a certain intended or predetermined speed.